Dietary vitamin C in pre-parturient dairy cows and their calves: blood metabolites, copper, zinc, iron, and vitamin C concentrations, and calves growth performance.

The aim of this study was to evaluate the effects of dietary vitamin C supplementation on blood parameters of pre-parturient (PP) dairy cows and growth performance and immune system of their newborn calves. Forty PP cows (at approximately 21 days before calving and an average weight 791 ± 50 kg) were allocated into two experimental treatments: (1) basal diet without vitamin C supplementation (CO) and (2) basal diet with 20 g of vitamin C supplementation from 21 days before calving to parturition (VC). After parturition, the experiment continued by grouping the calves into four dietary treatments with 8 calves in each treatment. The experimental treatments were (1) control calves with no vitamin C supplementation and from cows that received no vitamin C supplement (CON), (2) calves supplemented with 600 mg of vitamin C per day and from cows that received no vitamin C supplement (CVC), (3) calves supplemented with no vitamin C and from cows that received 20 g of vitamin C per day (MVC), and (4) calves supplemented with 600 mg of vitamin C per day and from cows that received 20 g of vitamin C per day (CMVC). Serum concentrations of glucose, HDL and LDL, cholesterol, triglycerides, total protein, and albumin of cows were not affected by vitamin C supplementation during pre-parturient period. However, cows that received VC diet had lower (P < 0.05) malondialdehyde (MDA) and aspartate aminotransferase (AST) concentrations, higher total antioxidant capacity (TAC), and vitamin C concentration in their blood compared to CO cows. Vitamin C supplementation had no effect on plasma iron, copper, and zinc concentrations of PP cows. Similarly, vitamin C supplementation had no effect on total feed intake and feed conversion ratio (FCR) of suckling calves. However, calves in the CMVC group had higher (P < 0.05) overall daily weight gain compared to the other groups. Calves in the CVC and CMVC groups had lower (P < 0.05) blood MDA concentration on days 7 and 21. The highest (P < 0.05) blood TAC level was recorded in CMVC calves. Control group calves had lower (P < 0.05) blood superoxide dismutase activity compared to the other calves. Blood levels of alanine aminotransferase on days 7 and 21 and aspartate aminotransferase on day 7 were higher (P < 0.05) for calves in the CON and MVC groups. Based on the results, vitamin C supplementation had positive health effects on the oxidative parameters of PP dairy cows and also improved the performance and health status of the calves.